package Classic150;

public class 验证回文串 {
    /*
        首尾双指针
     */
    public boolean isPalindrome(String s) {
        int left = 0;
        int right = s.length() - 1;
        while (left < right) {
            while (left < right && !Character.isLetterOrDigit(s.charAt(left))) left++;
            while (left < right && !Character.isLetterOrDigit(s.charAt(right))) right--;
            if (left < right) {
                if (Character.toLowerCase(s.charAt(left)) != Character.toLowerCase(s.charAt(right))) return false;
                left++;
                right--;
            }
        }
        return true;
    }
}
